The present invention relates to a portable shelter and more particularly to a thermally insulated, collapsible shelter especially suited for emergency use to combat hypothermia and to evacuate injured victims.
There is a strong need for a relatively small, compact emergency shelter for use by one or more survivor(s) of an airplane crash or other catastrophe in isolated, rugged terrain, where exposure to the elements poses a serious problem to the survivor(s). Such survivor(s) may have to survive on their own for up to 48 hours or even longer before rescuers locate the crash site or, once located, have time to reach the site. In the event of a crash, hypothermia or exposure is a serious problem for all concerned, particularly under harsh weather conditions, and is a critical problem for injured survivors suffering from shock or loss of blood. It is essential that the injured survivors, and under many conditions, all survivors, conserve body heat and keep as warm and dry as possible.
A tent or shelter suitable for this purpose must be light, sturdy and compact because most airplane crashes in rugged terrain happen to small, light planes capable of carrying only a few passengers and a small amount of gear and supplies. Obviously, larger commercial planes have the capacity to carry relatively large, elaborate shelters, but such is not the case with small planes. Not only would heavy, bulky emergency shelters be impractical as standard emergency equipment for small planes, but they would be ill-suited for air-drop by helicopter or small rescue plane to crash survivors in rugged terrain.
Ideally, the shelter should be self-supporting, as well as compact, since the crash area may be quite rocky, affording little or no level ground upon which to pitch the shelter. The shelter should be of simple construction and easy to set up, even by mobile injured survivors. It should be sturdy and capable of withstanding heavy snowfall and high winds. Most importantly, the shelter should be virtually waterproof and afford maximum protection from the environment under a wide variety of conditions. Ideally, it would also be desirable to use the shelter to evacuate the injured survivor(s) to safety.
Prior tents and shelters, some of which are designed for emergency use, do not adequately meet the foregoing criteria. Two examples of inflatable tents are shown in U.S. Pat. No. 4,000,585 to Denaro and U.S. Pat. No. 3,457,684 to Wood. The Denaro tent is not self-supporting without its internal frame which adds weight to the tent and complexity to its assembly, making it ill-suited as a survival shelter in rugged, remote areas.
Although the tent shown in Wood does not require an internal frame, it shares another important shortcoming with the Denaro tent. Both are of the "camping tent" type and ill-suited for emergency survival use because they are not adequately thermally insulated. Although both tents have panels formed of inflatable tubular cells, a significant amount of heat is lost at the seams between such cells and at the adjoining edges of such panels, where no insulation, air or otherwise, exists between the tent's inner and outer surfaces. In the case of the Wood tent, the end panels are also not insulated. Without a sleeping bag or blankets, it is unlikely that a crash survivor, particularly an injured one, could survive in these tents under adverse conditions for very long.
Two tents ostensibly designed for emergency use are shown in U.S. Pat. Nos. 2,830,606 and 2,819,724 to Daugherty and Barker, respectively. The Daugherty tent, like the Denaro and Wood tents, suffers significant heat loss at the seams between its tubular air chambers, as well as at its end panels which are not insulated. With this tent, survival under harsh conditions is questionable. Equally important, its seams, as well as the seams of the Denaro and Wood tents, are prone to allowing moisture into the tent when they are exposed to continuous rain or other forms of moisture. This is a very common problem with camping type tents, even when a rain fly is used. This problem has potentially dangerous consequences when the weather conditions are severe because a wet victim is much more prone to suffer from hypothermia than one who is dry.
The Barker tent, which is designed for use in Arctic regions, appears to be the only prior shelter having a true "double-wall" construction that alleviates the heat loss problem caused by the "seams" of the foregoing tents. Although this tent is quite large and evidentally designed to shelter several people comfortably, it does have a few of the desired characteristics for a small survival shelter suited for use under severe conditions. It appears to provide a frameless shelter with a high degree of thermal insulation. It also appears to be fairly easy to set-up.
However, aside from the difficulty of using a large tent of this type in rugged mountainous terrain common to Western parts of the United States, this tent does not appear to be adequately supported to withstand heavy snowfall or snowpack which could possibly bury the tent. The inner and outer walls of the tent, which form an air pocket therebetween, are connected by thin threads which provide little, if any, structural support for the tent. The sole supporting means for the tent is the air pressure supporting the walls when the tent is inflated. Consequently, it is quite likely that high winds or heavy snow accumulation on the top of the tent would cause the tent to deform, if not buckle altogether. As a further disadvantage, the Barker tent lacks suitable means for efficiently controlling the amount of heat lost to the environment, a feature desirable in less severe conditions where the tent could become uncomfortably warm because it is so well insulated. This obviously would not be a problem with the other tents discussed because of their relatively poor insulating traits.
None of the foregoing tents are suited for use in evacuating to safety an injured victim who should remain as immobile as possible. Typically, the victim(s) of an airplane crash in rugged terrain will have to be evacuated to an area accessible to a vehicle or helicopter. With all of the foregoing tents, the victim would have to be removed from the tent before being evacuated.
Of slight relevance in this regard are U.S. Pat. Nos. 3,986,505, 4,124,908 and 4,301,791 to Power, Burns, et al. and Franco, respectively, which all show litter-type devices for transporting injured victims. All three such litters have one or more covers which envelope the victim to help keep the victim warm. In the case of Power and Burns, two overlapping covers are secured in place by Velcro-type fasteners. The Franco litter supports the victim on an inflatable bed. None of these devices are suited for use as a shelter in adverse weather conditions.
Accordingly, there is a need for a small emergency shelter suited for use in rugged terrain under severe weather conditions that is light, portable, easy to set-up and stands up to high winds and heavy snowfall without buckling.
A primary object of the invention is to provide a collapsible emergency shelter suited for use in rugged terrain under all types of weather conditions that stands up to high winds and heavy snow conditions without buckling.
A second object of the present invention is to provide shelter, as aforesaid, that has a high degree of insulation against heat loss and is virtually waterproof.
A further object of the invention is to provide a shelter, as aforesaid, that is light, portable and easy to set-up.
Yet another object of the invention is to provide a shelter, as aforesaid, that is entirely self-supporting without a frame, poles, stakes or the like.
Still another object of the present invention is to provide a shelter, as aforesaid, with means for effectively controlling the amount of heat loss from the shelter.
Another object of the present invention is to provide a shelter suitable for evacuating safely an injured victim and affording medical personnel quick access to the victim while the victim remains immobile.
Other objects will become apparent from the following detailed description of a preferred embodiment and the drawings.